This invention relates to preserved ophthalmic compositions. More particularly, the present invention relates to preserved ophthalmic compositions, for example, useful in administering a therapeutic component to the eyes, and for example, to care for contact lenses, which include one or more peptides and/or peptide derivatives as antimicrobial agents.
Various compositions, such as solutions, emulsions and suspensions are used in association with administering therapeutic components to the eyes. For example, an oil-in-water emulsion may be used as a carrier for a therapeutic component to be administered to the eyes.
At present, no safe effective preservative exists for an oil-in-water emulsion product. This is because the most acceptable preservative, benzalkonium chloride, loses its effectiveness due to partitioning into the oil phase. As a result only single dose containers of oil-in-water emulsion ophthalmic compositions can be marketed up to this time.
Use of single dose containers to store ophthalmic compositions prevents contamination and growth of microorganisms. However, single dose containers are inconvenient to use and are expensive for the consumer. Appropriate use of an effective preservative will allow for production of multidose containers of preserved ophthalmic compositions such as oil-in-water emulsions.
Various compositions are used in association with contact lenses to ensure that the lenses may be safely, comfortably and conveniently worn. Contact lens care compositions, for example, cleaning compositions, wetting compositions, conditioning compositions and the like, often utilize at least one preservative, depending on the type of composition, for preserving the lens care composition itself.
A preserved contact lens care composition has sufficient antimicrobial activity so that when the composition is contacted with a contact lens substantially no increase in the microorganism population on the lens or in the composition is obtained. A preserved contact lens care composition may be termed a microbiostatic composition. Contact lens care compositions are often preserved to prevent any substantial increase in, or to gradually decrease, the population of contaminating microorganisms in the compositions and, thereby, to extend their shelf life.
Various compounds are known for use as preserving agents in preserved ophthalmic compositions. Examples include thimerosal, benzalkonium chloride and chlorhexidine. However, these preserving agents are known to exhibit ocular toxicity which may result in irritation or sensitivity to the eye. Further, a soft contact lens, a rigid gas permeable contact lens (RGP) or a hard contact lens can absorb or adsorb these compounds. This causes the contact lens to retain the irritating compound and contributes to the eye irritation and eye sensitivity which may result.
Thus, it is readily apparent that a continuing need exists for safe and efficacious compositions that can be used to preserve ophthalmic compositions.